1. Field of the Invention
The present invention relates to a technology for generating image display data.
2. Description of the Related Art
Recently, it has been widely performed to scan paper-based graphics or documents as images with a scanner to digitalize them along with a cost reduction of a scanner, enforcement of the electronic document law, or the like. Digitized graphics or documents are stored as image data files, which brings about an effect of saving storage space.
However, it is difficult to search for a desired image data file from among a large number of image data files in a recording medium such as a hard disk.
To solve this problem, software for managing image data files has been developed and widely used, with which images based on a plurality of image data files stored in a recording medium are displayed in a list as size-reduced images called thumbnails. With this software, a user can roughly identify each image by the thumbnails and can easily find a desired image data file by relying on ambiguous memory of the image. Upon confirming that the thumbnail displayed on the screen is the desired image, the user can cause the details of the image to be displayed on the screen by starting image display software by clicking the thumbnail with a mouse.
An information search device is disclosed in Japanese Patent No. 3614235 as a device utilizing the technology of displaying a list of such thumbnails.
However, it is difficult to specify the area that a user has already confirmed in the conventional thumbnail list. Therefore, if the user scrolls the thumbnail list incorrectly, an operation of confirming thumbnails becomes complex. Specifically, if the number of the image data files is large, not all the thumbnails corresponding to the image data files are displayed on the screen simultaneously. Therefore, some thumbnails in part of the thumbnail list (hereinafter, “display area”) are displayed on the screen. The user scrolls the screen with a mouse or the like to move the display area if needed, and displays thumbnails that were not displayed on the screen. If the user operates the mouse incorrectly to scroll the display area quickly and the user could not confirm thumbnails, the user needs to scroll the display area in a backward direction to confirm the thumbnails. In this case, the display area is desirably scrolled in the backward direction at a stroke to return to the preceding state instantly; however, the user cannot determine a scrolling amount to return to the preceding state. Therefore, the user needs to scroll the display area slowly in the backward direction to confirm thumbnails one by one until the user finds a thumbnail that the user has already seen before. Thereafter, if the user needs to confirm unconfirmed thumbnails, the user needs to move the display area to an unconfirmed-area by scrolling the display area in a forward direction. In this case, the user needs to scroll the display area slowly in the forward direction and confirm the thumbnails that the user has already confirmed for a while again, which is useless.